cf0f02d04a
Use LLC for the receive path of Spanning Tree Protocol packets. This allows link local multicast packets to be received by other protocols (if they care), and uses the existing LLC code to get STP packets back into bridge code. The bridge multicast address is also checked, so bridges using other link local multicast addresses are ignored. This allows for use of different multicast addresses to define separate STP domains. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
159 lines
3.6 KiB
C
159 lines
3.6 KiB
C
/*
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* Handle incoming frames
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* Linux ethernet bridge
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*
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* Authors:
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* Lennert Buytenhek <buytenh@gnu.org>
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*
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* $Id: br_input.c,v 1.10 2001/12/24 04:50:20 davem Exp $
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <linux/netdevice.h>
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#include <linux/etherdevice.h>
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#include <linux/netfilter_bridge.h>
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#include "br_private.h"
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const unsigned char bridge_ula[6] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
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static void br_pass_frame_up(struct net_bridge *br, struct sk_buff *skb)
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{
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struct net_device *indev;
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br->statistics.rx_packets++;
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br->statistics.rx_bytes += skb->len;
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indev = skb->dev;
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skb->dev = br->dev;
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NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL,
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netif_receive_skb);
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}
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/* note: already called with rcu_read_lock (preempt_disabled) */
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int br_handle_frame_finish(struct sk_buff *skb)
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{
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const unsigned char *dest = eth_hdr(skb)->h_dest;
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struct net_bridge_port *p = rcu_dereference(skb->dev->br_port);
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struct net_bridge *br;
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struct net_bridge_fdb_entry *dst;
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int passedup = 0;
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if (!p || p->state == BR_STATE_DISABLED)
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goto drop;
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/* insert into forwarding database after filtering to avoid spoofing */
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br = p->br;
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br_fdb_update(br, p, eth_hdr(skb)->h_source);
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if (p->state == BR_STATE_LEARNING)
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goto drop;
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if (br->dev->flags & IFF_PROMISC) {
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struct sk_buff *skb2;
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skb2 = skb_clone(skb, GFP_ATOMIC);
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if (skb2 != NULL) {
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passedup = 1;
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br_pass_frame_up(br, skb2);
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}
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}
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if (is_multicast_ether_addr(dest)) {
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br_flood_forward(br, skb, !passedup);
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if (!passedup)
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br_pass_frame_up(br, skb);
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goto out;
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}
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dst = __br_fdb_get(br, dest);
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if (dst != NULL && dst->is_local) {
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if (!passedup)
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br_pass_frame_up(br, skb);
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else
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kfree_skb(skb);
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goto out;
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}
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if (dst != NULL) {
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br_forward(dst->dst, skb);
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goto out;
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}
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br_flood_forward(br, skb, 0);
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out:
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return 0;
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drop:
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kfree_skb(skb);
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goto out;
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}
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/* note: already called with rcu_read_lock (preempt_disabled) */
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static int br_handle_local_finish(struct sk_buff *skb)
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{
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struct net_bridge_port *p = rcu_dereference(skb->dev->br_port);
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if (p && p->state != BR_STATE_DISABLED)
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br_fdb_update(p->br, p, eth_hdr(skb)->h_source);
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return 0; /* process further */
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}
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/* Does address match the link local multicast address.
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* 01:80:c2:00:00:0X
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*/
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static inline int is_link_local(const unsigned char *dest)
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{
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return memcmp(dest, bridge_ula, 5) == 0 && (dest[5] & 0xf0) == 0;
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}
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/*
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* Called via br_handle_frame_hook.
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* Return 0 if *pskb should be processed furthur
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* 1 if *pskb is handled
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* note: already called with rcu_read_lock (preempt_disabled)
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*/
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int br_handle_frame(struct net_bridge_port *p, struct sk_buff **pskb)
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{
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struct sk_buff *skb = *pskb;
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const unsigned char *dest = eth_hdr(skb)->h_dest;
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if (p->state == BR_STATE_DISABLED)
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goto err;
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if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
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goto err;
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if (unlikely(is_link_local(dest))) {
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skb->pkt_type = PACKET_HOST;
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return NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
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NULL, br_handle_local_finish) != 0;
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}
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if (p->state == BR_STATE_FORWARDING || p->state == BR_STATE_LEARNING) {
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if (br_should_route_hook) {
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if (br_should_route_hook(pskb))
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return 0;
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skb = *pskb;
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dest = eth_hdr(skb)->h_dest;
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}
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if (!compare_ether_addr(p->br->dev->dev_addr, dest))
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skb->pkt_type = PACKET_HOST;
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NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
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br_handle_frame_finish);
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return 1;
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}
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err:
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kfree_skb(skb);
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return 1;
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}
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